For this trophy I'd recommend playing on Creative Mode, which is unlocked when you complete the game by getting the true ending. On Creative, you have unlimited health, stamina, hunger, and thirst. Start on Creative and complete the game like you normally would, including getting the keycard, rebreather, and climbing axe. Then you can jump in the sinkhole from above and make your way to the final boss. The only thing to note, other than not purposefully killing animals, is to not cut down any trees, since there's a chance that a falling tree could kill one by accident. Also, be careful about using explosives, molotovs, and anything else that might put the life of an animal in harm's way. If done correctly, the trophy will pop after the cutscenes that follow the true ending.